MEMS technology integrates electrical components and mechanical components on a common silicon substrate by using micro-fabrication technology. Integrated circuit (IC) fabrication processes, such as photolithography processes and other microelectronic processes, form the electrical components. The IC fabrication processes typically use materials such as silicon, glass, and polymers. Micro-machining processes, compatible with the IC processes, selectively etch away areas of the IC or add new structural layers to the IC to form the mechanical components. The integration of silicon-based microelectronics with micro-machining technology permits complete electro-mechanical systems to be fabricated on a single chip. Such single chip systems integrate the computational ability of microelectronics with the mechanical sensing and control capabilities of micro-machining to provide smart devices.
One type of MEMS is a micro-fluidic system. Micro-fluidic systems include components such as channels, reservoirs, mixers, pumps, valves, chambers, cavities, reaction chambers, heaters, fluidic interconnects, diffusers, nozzles, and other micro-fluidic components. These micro-fluidic components typically have dimensions between a few micrometers and a few hundreds of micrometers. These small dimensions minimize the physical size, the power consumption, the response time and the waste of the micro-fluidic system. Such micro-fluidic systems may provide wearable miniature devices located either outside or inside a human body or an animal body.
Applications for micro-fluidic systems include genetic, chemical, biochemical, pharmaceutical, biomedical, chromatography, IC cooling, ink-jet printer head, medical, radiological, environmental, as well as any devices that require liquid or gas filled cavities for operation. Such application may involve processes related to analysis, synthesis and purification. The medical applications include diagnostic and patient management such as implanted drug dispensing systems. The environmental applications include detecting hazardous materials or conditions such as air or water pollutants, chemical agents, biological organisms or radiological conditions. The genetic applications include testing and/or analysis of DNA.
An anti-microbial filter is a device that filters out microorganisms in a fluidic system. Anti-microbial filters are typically used for fluid purification, such as in air, water and drug delivery systems. In drug delivery systems, anti-microbial filters are used to prevent microorganisms in a human or an animal body from reaching the fluid source of the drug delivery. Some anti-microbial filters are made with holes that are large enough to permit fluid to flow through the filter in one direction, but small enough to prevent the microorganisms from moving through the filter in the opposite direction. Anti-microbial filters may also have a coating, such as silver, disposed on the downstream side of the filter that prevents some microorganisms from adhering to the filter and kills other microorganisms that contact the coating. Some anti-microbial filters have a long, narrow, winding path, otherwise known as a torturous path, which permits fluid to flow in one direction through the path while inhibiting the flow of microorganisms in the opposite direction. Anti-microbial filters have been made on a macro scale. However, making anti-microbial filters on a micro scale presents special challenges, such as the construction of very small holes with precision while being cost effective, manufacturable and reliable.
Accordingly, it would be desirable to have an anti-microbial filter that is small enough to be used in a micro-fluidic system. The anti-microbial filter would be constructed using micro-machining processes to permit it to be integrated into a micro-fluidic system. The micro-machining process would be precise and cost effective. Thus, the anti-microbial filter would be easy to manufacture and of high quality.